Emergency Derm Flashcards
6 features of urticaria
Erythematous Blanching Oedematous Non-painful Pruritic Develop rapidly (usually minutes)
Give 3 allergen triggers for urticaria
Drugs
Food
Insect bites
What is angio-oedema?
Swelling involving the dermis + subcutaneous tissue
Can occur with urticaria
Often of face, tongue, lips
What are major mediators in urticaria and angio-oedema?
Mast cells releasing histamine
Ix for urticaria
FBC
ESR
CRP
Tx for acute urticaria +/- angio-oedema WITHOUT airway involvement
Trigger avoidance
Antihistamines
Corticosteroids e.g. Prednisolone PO if severe
Tx for acute urticaria +/- angio-oedema WITH airway involvement
Adrenaline
Corticosteroids
Antihistamines IV
3 features of erythema multiforme
Mild self-limiting hypersensitivity inflammatory condition
Target lesions that resemble a bull’s eye
Erupt over 24-48 hours, last 1-2 weeks.
Which 2 infections are most commonly associated with erythema multiforme?
Herpes simplex virus
Mycoplasma pneumoniae
Which sites are most commonly affected in erythema multiforme?
Distal extremities (Acral) Limited/ absent mucosal involvement
Ix for erythema multiforme
FBC: raised WCC
PCR/ serology for HSV
Tx for erythema multiforme minor
Topical emolient
Topical/ oral corticosteroids
Tx for erythema multiforme major
Topical emolient
Oral/ IV corticosteroids
Tx for infections in erythema multiforme
Acyclovir if HSV
Macrolide/ Doxycycline if mycoplasma pneumoniae
What is Stevens-Johnson Syndrome?
Severe skin detachment with mucocutaneous necrosis
Describe the severity of Stevens-Johnson syndrome
More severe form of erythema multiforme major + a less severe manifestation of toxic epidermal necrolysis (TEN)
3 drug classes that may cause Stevens-Johnson syndrome
Anticonvulsants
Abx
NSAIDs
3 infections that may lead to Stevens-Johnson syndrome
URTI
Mycoplasma pneumoniae
Herpes
Which sign may present in Stevens-Johnson syndrome?
Nikolsky’s sign
Epidermal layer easily sloughs off when pressure is applied to blistered/ erythematous area.
Ix for definitive diagnosis of SJS
Skin biopsy
Tx for SJS
Withdrawal of causative agent Prophylactic anticoagulant- Enoxaparin PPI- Omeprazole Dressings, topical antibacterial + emolient Ophthalmological examination
